Race, Ethnicity on Job Application form? Behind the times? Discrimination? or Other?

Im a Canadian RN
New to The USA Nursing Job Market.
One thing that really caught my attention, was on all the application forms.

Most Hospitals will have a generous section pertaining to your Ethnicity or Race.

I can remember in Canada when questions like these stopped appearing on applications, as it had no purpose - other than the possibility to discriminate.

Can anyone shed some light as to why the US (One of the supposedly world leaders) is still engaged in this practice?

Is there some logic to it?

Is it a Pro or Con to place a check in the box (if provided): "Rather not answer"

Anyone from other countries care to comment on similar trends in their country?